ASO Author Reflections: Postoperative Inflammatory Markers as a Surveillance Tool in Colorectal Peritoneal Carcinomatosis

Background The prognostic significance of inflammatory markers in solid cancers is well-established, albeit with considerable heterogeneity. This study sought to investigate the postoperative inflammatory marker trend in peritoneal carcinomatosis (PC), with a focus on colorectal PC (CPC), and to propose optimal surveillance periods and cutoffs. Methods Data were collected from a prospectively maintained database of PC patients treated at the authors' institution from April 2001 to March 2019. The platelet-lymphocyte ratio (PLR), the neutrophil-lymphocyte ratio (NLR), and the lymphocyte-monocyte ratio (LMR) were collected preoperatively and on postoperative days 0, 1 to 3, 4 to 7, 8 to 21, 22 to 56, and 57 to 90 as averages. Optimal surveillance periods and cutoffs for each marker were determined by maximally selected rank statistics. The Kaplan-Meier method and Cox proportional hazard regression models were used to investigate the association of inflammatory markers with 1-year overall survival (OS) and recurrence-free survival (RFS) using clinicopathologic parameters. Results The postoperative inflammatory marker trend and levels did not differ between the patients with and those without hyperthermic intraperitoneal chemotherapy (HIPEC). Low postoperative LMR (days 4-7), high postoperative NLR (days 8-21), and high postoperative PLR (days 22-56) were optimal for prognosticating poor 1-year OS, whereas high postoperative PLR and NLR (days 57-90) and low postoperative LMR (days 8-21) were associated with poor 1-year RFS. A composite score of these three markers was prognostic for OS in CPC. Conclusions The reported cutoffs should be validated in a larger population of CPC patients. Future studies should account for the inflammatory response profile when selecting appropriate surveillance periods.